ABSTRACT
Agriculture in Thailand was the most important sector in the economy before the manufacturing sector started to play an increasing role in the late 1970s. Currently the agricultural sector provides employment for half of the population. Panyakul stated that irrigation is one of the important factors for the success of rice cultivation in central Thailand. Irrigation technologies are helping supply water to farms and control water levels. However, they may cause problems as a consequence of weed dissemination in irrigation water from one place to another. Agricultural statistics show that since the major agricultural changes have occurred, the greatest cropped area and production of rice are in the north-eastern region. In the mid-eighteenth century, the principal feature of the Thai rural sector was small-scale survival or subsistence farming which was directed at meeting the basic needs of the family, with additional produce for barter exchange or for 'tribute' to the local elite.
